In order to direct laser energy in the I-R range, electrodes in these devices must be transparent. For example, in an article in Applied Physics Letters, vol. 67, p 2246 (1995), Phillips et al show that zinc indium oxide (ZIO) can be grown as a thin film by the use of the pulsed laser deposition techniques and by dc reactive sputtering. The optical transmission characteristics of such film is significantly better than other transparent conducting oxides and has a conductivity approaching that of indium-tin-oxide (ITO). ZIO is noted for its superior transmission in the 1 to 1.5 micron range and is thus desirable for use in infrared devices where transparent electrodes are essential.
Thus, there exists a need and market for a thin film material which is both highly conductive and transparent from visible to wavelengths beyond 10 microns. There has now been discovered films that meet this need.